The present invention relates to an improved device for reducing the lag in position of a non-linear subsidiary or copying system for a regulation loop for turbo generators.
HISTORY OF THE RELATED ART
Applicant's French Pat. No. 2 496 922 discloses a process for automatically reducing the lag in position of a non-linear subsidiary or copying system for a regulation loop for turbo-generators, as well as a device for carrying it out.
It will be recalled that the speed of a turbine is a function of at least one parameter. For example, the speed of a PELTON turbine is directly a function of at least the position of an injector which regulates the flowrate and of which the speed of displacement if relatively slow, with the result that actuation of this adjusting member does not allow a rapid variation of the flowrate, therefore of the power and consequently of the speed of the turbine. Furthermore, the speed of the turbine is also a function of another parameter which is, for example for PELTON turbines, the position of the deflectors placed in front of the injectors.
The prior document mentioned above relates to a process for adapting the signal emitted by the primary circuit regulator as a function of the difference in frequency noted between the frequency of the current produced and the one desired, and the real value of the position of the adjusting member. In the process, the two thresholds of saturation of at least one of the proportional (P), integral (I) or derivative (D) action circuits are acted upon, the values of these two thresholds of saturation themselves being determined as a function of the real position of the adjusting member and of the sum of the responses of the other action circuits not concerned.
The document in question also describes a device for carrying out the above process.
Although that invention makes it possible considerably to reduce the lag of the member for adjusting the speed of the turbine or the like with respect to the drop in its speed (and of the frequency of the current) due to an overload, the device described in the document in question is relatively complex in construction, leading to a high cost price.